Update CI workflow to clean build before testing code generation

Author: nakamura-to

.github/workflows/ci.yml

@@ -31,10 +31,10 @@ jobs:
         run: chmod +x gradlew
 
       - name: Test plugin (generate Java code)
-        run: ./gradlew domaCodeGenJavaAll build
+        run: ./gradlew clean domaCodeGenJavaAll build
 
       - name: Test plugin (generate Kotlin code)
-        run: ./gradlew domaCodeGenKotlinAll build
+        run: ./gradlew clean domaCodeGenKotlinAll build
 
       - name: Set version
         id: set-version